In a group of healthy postmenopausal women whose body fat distribution and body fat mass independently range from lower (gynoid) to upper (android) distribution and from lower (lean) to higher (obese) percent fat we have found a trend to greater percent body fat with increasing age despite the absence of a significant relationship between age and body mass index. Data also suggest that dual energy x-ray absorptiometry yields estimates of body composition comparable to those obtained by hydrodensitometry. There were independent inverse correlations of waist to hip ratio (p<0.03), but not of age of body mass index, with 12 hour pulsatile GH levels and GHRH- stimulated GH peaks. These findings suggest an age-independent decrease in GH secretion attributable to android habitus in postmenopausal women. Oral estrogen treatment, produced a trend to increased spontaneous GH levels, which was significant only for the area under the peaks. Transdermal estrogens tended to decrease mean GH peak amplitude, and to increase 12 h mean GH. Oral, but not transdermal, estrogens significantly decreased basal and stimulated IGF-I, while transdermal estrogens had a greater effect on reducing IGF Binding Protein-3 than did oral estrogens. In another ongoing study of healthy women age 65-75 y treated with constant combined oral estrogen with and without low dose daily progestin, minor breast tenderness has been the only adverse effect reported to date. Four women receiving estrogen-progestin co-therapy experienced vaginal bleeding within the first three months of study requiring an increase in progestin dose.